1. Field of the Invention
The invention generally relates to resonators, oscillators, and communication apparatuses. More particularly, the invention relates to a resonator utilizing mechanical oscillations, an oscillator including the resonator, and a communication apparatus incorporating the oscillator.
2. Description of the Related Art
With the recent development of radio communication technology, the reduction in size and weight has been demanded on communication apparatuses utilizing the radio communication technology. Into the area of RF signal-processing which has been considered difficult so far to realize the reduction, micro-electromechanical system (MEMS) technology, which is fabricating minute mechanical structures making use of the semiconductor microfabrication technology, has been introduced.
An example of the MEMS technology includes a mechanical resonator utilizing mechanical resonance. Since RF device elements such as a filter, oscillator, mixer and other similar devices using the mechanical resonator are relatively small in size and can be integrated, the application of the resonators and RF elements is expected into the sectors of telecommunication. The technology of the mechanical resonator has been disclosed in Japanese Unexamined Patent Application Publication No. 2006-33740 and U.S. Pat. No. 6,249,073.